A fixed wireless access terminal is typically installed in a permanent or semi-permanent position within a subscriber's premises. A network of basestations connectable to such fixed wireless access terminals through wireless connections provide normal telephony services and offer an alternative to the conventional twisted pair telephone connections.
In state of the art fixed wireless access terminals, the concept of displaying a signal strength measurement such as the RSSI (radio signal strength indicator) is well known. The intent is to assist a subscriber in locating the fixed access terminal so as to optimize the communications with a basestation. The manner in which this is typically done is to display a bar graph using six characters of a display forming part of the fixed wireless access terminal. There are numerous problems with this approach. To begin, the resolution of the display is typically 10 dB per character. This is insufficient to allow the subscriber to optimally locate the terminal. In addition, there may be a large amount of CCI (co-channel interference) on the forward link (from a basestation to the terminal). This problem is serious in high capacity cellular networks where the desire to reuse frequencies many times can degrade the SIR (signal to interferer ratio) such that the BER (bit error rate) of the forward traffic link is seriously degraded. In such situations, the RSSI will indicate a strong signal strength, but the quality of the signal will not be sufficient. The RSSI alone will not indicate the problem with the BER because it includes both components of the proper signal and the interfering signals.
Another problem with state of the art systems is that the displayed RSSI levels only reflect the quality of the forward link. The result of this is that the user may position the set such that his/her reception characteristics are good, but such that the reception at the other end of the connection is poor.